The centre of the Catholic Church is the Mass. The Liturgy of the Eucharist is an ancient practice which goes back to the Last Supper with the first Mass. Its the main way that we worship God and petition requests to Him. This is also the most effective means to help the holy souls.
How does the Mass help the souls in Purgatory? This is the most powerful way to pray for them, followed by the Rosary. More souls are released by the Mass than any other means. St. Jerome said that “for every Mass devoutly celebrated, many souls leave Purgatory and fly to Heaven”. St. Bernadette, who had a great devotion for the holy souls, would tell her fellow religious sisters “I have heard Mass for the souls in Purgatory: nothing but the Precious Blood of Jesus applied for them, can liberate them”. St. John Vianney (the Curé d’Ars) emphasized that the Mass is greater than any works preformed, “All good works taken together cannot equal the value of one Holy Mass; because they are the works of men, whereas Holy Mass is the work of God.” The Mass is the most effective way to help the holy souls in Purgatory.
We can help the holy souls by offering a Mass for them. This is involves speaking to a priest and arranging a date for the Mass. The cost in Canada for this is typically $10, but this is a free will offering and can be changed by the priest. It will also vary around the world. Poorer countries would require smaller amounts of money. I have to stress that you can’t buy someone out of Purgatory. This isn’t a service that the Church markets to increase its cash flow. If it was, then its a very poor way to make money. Considerably more money is made through offerings on a Sunday Mass.